This review puts into perspective the present state and prospects for controlling quantum phenomena in atoms and molecules. The topics considered include the nature of physical and chemical control objectives, the development of possible quantum control rules of thumb, the theoretical design of controls and their laboratory realization, quantum learning and feedback control in the laboratory, bulk media influences, and the ability to utilize coherent quantum manipulation as a means for extracting microscopic information. The preview of the field presented here suggests that important advances in the control of molecules and the capability of learning about molecular interactions may be reached through the application of emerging theoretical concepts and laboratory technologies.
A new physical implementation for quantum computation is proposed. The vibrational modes of molecules are used to encode qubit systems. Global quantum logic gates are realized using shaped femtosecond laser pulses which are calculated applying optimal control theory. The scaling of the system is favorable, sources for decoherence can be eliminated. A complete set of one and two quantum gates is presented for a specific molecule. Detailed analysis regarding experimental realization shows that the structural resolution of today's pulse shapers is easily sufficient for pulse formation.
High
degrees of delithiation of layered transition metal oxide
cathode active materials (NCMs and HE-NCM) for lithium-ion batteries
(LIBs) was shown to lead to the release of singlet oxygen, which is
accompanied by enhanced electrolyte decomposition. Here, we study
the reactivity of chemically produced singlet oxygen with the commonly
used cyclic and linear carbonate solvents for LIB electrolytes. On-line
gassing analysis of the decomposition of ethylene carbonate (EC) and
dimethyl carbonate (DMC) reveals different stability toward the chemical
attack of singlet oxygen, which is produced in situ by photoexcitation
of the Rose Bengal dye. Ab initio calculations and
on-the-fly simulations reveal a possible reaction mechanism, confirming
the experimental findings. In the case of EC, hydrogen peroxide and
vinylene carbonate (VC) are found to be the products of the first
reaction step of EC with singlet oxygen in the reaction cascade of
the EC chemical decomposition. In contrast to EC, simulations suggested
DMC to be stable in the presence of singlet oxygen, which was also
confirmed experimentally. Hydrogen peroxide is detrimental for cycling
of a battery. For all known cathode active materials, the potential
where singlet oxygen is released is found to be already high enough
to electrochemically oxidize hydrogen peroxide. The formed protons
and/or water both react with the typically used LiPF6 salt
to HF that then leads to transition metal dissolution from the cathode
active materials. This study shows how important the chemical stability
toward singlet oxygen is for today’s battery systems and that
a trade-off will have to be found between chemical and electrochemical
stability of the solvent to be used.
Laser pulses with stable electric field waveforms establish the opportunity to achieve coherent control on attosecond time scales. We present experimental and theoretical results on the steering of electronic motion in a multielectron system. A very high degree of light-waveform control over the directional emission of C(+) and O(+) fragments from the dissociative ionization of CO was observed. Ab initio based model calculations reveal contributions to the control related to the ionization and laser-induced population transfer between excited electronic states of CO(+) during dissociation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.